This grilled cheese/burger hybrid is said to have been invented in the 1940s or ’50s when the popularity of drive-in restaurants and diners was on the rise. Today, the patty melt stands as a shining, somewhat greasy example of the classic American diner sandwich. Thin patties of ground beef are cooked until browned, covered with Swiss cheese and plenty of caramelized onions, and put between slices of rye bread. Then the whole sandwich is grilled until melty and crunchy. Here we used Chef Gabrielle Hamilton’s tip for replacing the butter with mayonnaise to get the best browning and flavor. Eat with a heaping pile of crispy french fries.